What could possibly be good about anxiety? Anyone living in our land of yoga and silent meditation retreats knows anxiety is killing us. It's straining our hearts, damaging our brains and shortening our telomeres - those little bookends on our chromosomes that protect our DNA when cells replicate.

We've cast anxiety as our modern plague. But this is so very unfair.

For all its torment, fear is a marvelous beast. The brain structures that join forces to produce it are highly preserved across species, indicating that fear is a pretty handy response to threat whether you're a mouse or a venture capitalist. In a state of heightened mental and bodily awareness, time slows down, breathing accelerates, muscles fill with oxygenated blood, and our brains absorb and integrate information in an appallingly efficient form of learning called fear conditioning.

Fear is contagious

That fear is so universal and influential is testament to its historic importance for survival, but fear is also terrifically transmittable. Brain imaging studies demonstrate that in humans, viewing an image of a frightened face triggers our own fear centers below the level of our conscious awareness. Watching a herd of antelope evading a lion, we can appreciate how contagious anxiety unifies the group's response even in members who can't see the threat.

Not only do we catch fear from each other, we pass it to our offspring. Both anxiety disorders and trait anxiety - a tendency to worry - are extremely heritable; thus my daughters may suffer the same performance anxiety that kept their mother up all night before track meets.

Most of us know from personal experience that fear is both psychological (dread, hopelessness, terror) and physical (pounding heart, dry mouth, trembling). Sufferers of anxiety disorders are stricken with both these components to an agonizing, paralyzing extreme that non-sufferers cannot fathom.

Anxiety is fear with the added element of anticipation, and one major feature of an anxiety disorder is a torturous, anticipatory fear of fear. This fear of fear is what clinicians who treat anxiety disorders call "meta-emotion" - how we feel about our feelings.

Humans are complicated. We can feel mad about feeling sad, we can feel anxious about feeling anxious. With or without an anxiety disorder, we all experience this phenomenon. I can think back to many a sweaty, fluorescent classroom moment when I clutched a No. 2 pencil in my hand and thought, "I'm terrified that my anxiety's going to make me choke." Boom. Meta-emotion.

But meta-emotion can work in our favor. Sports psychologists know that reframing anxiety as a state of mind signifying readiness for challenge yields better physical performance than attempting to reduce athletes' anxiety. Recent studies of test-taking anxiety suggest that a shift from extinguishing to harnessing anxiety may offer advantage in settings of heightened cognitive challenge, as well.

When anxiety feels appropriate, we are spared the meta-emotion, fear of fear, and better able to get on with the task at hand. It can be helpful to remember that the biological purpose of anxiety is performance enhancement.

Good qualities

We might even embrace our misunderstood Achilles' heel if we judge anxiety on its own merits. Trait anxiety associates with some wonderfully adaptive stuff. Highly conscientious, honest, detail oriented, performance driven, socially responsible, self-controlled: These are qualities I bear witness to in my patients.

Specializing in the treatment of anxiety, I'm struck by these positive traits that commingle with the debilitating symptoms of everything from panic to obsessive-compulsive disorder. Studies demonstrating that top performers in high-responsibility professions tend to be worriers hint at a bigger picture. For although the traits that sort with anxiety may drive an individual toward high achievement, they also benefit the rest of us in a societal "win-win." Being honest, responsible and self-controlled are pro-social traits. "Pro-social" may sound synonymous with "down to party," but it's actually a term for behavior likely to benefit society as a whole.

It behooves us to think better of our anxiety, our individual and collective anxiety, and relinquish our fear of fear. After all, you know who displays the least amount of trait anxiety? Sociopaths. Let's silently meditate on that.

Tracy Foose, M.D., is an assistant clinical professor at UCSF School of Medicine. She is the director of Adult Psychotherapy Clinics and serves as co-director of the Anxiety Disorders Program at UCSF with a clinical focus on general anxiety disorder, panic and social anxiety.